This invention relates to an electric motor coil element and a method of manufacturing the same.
Various electric motors are in use such as the moving-coil, coreless, slotless and brushless types. The rotor or stator of these motors is generally constructed by winding an electrically conductive wire around the peripheral surface of a cylindrical body. Among the motors comprising such rotor or stator is a disk type motor whose rotor or stator is formed of a flat or disk shaped coil.
A known method of manufacturing particularly a cylindrical motor coil includes the so-called skew winding method (also referred to as "a honeycomb method") described in U.S. Pat. No. 3,191,081 and the bell method. These methods consist in winding a wire around a columnar bobbin to provide a coil of a prescribed shape. Therefore, the conventional methods have the drawbacks that difficulties arise in mechanically winding a wire at high speed resulting in a decline in the coil manufacturing efficiency. Further disadvantages of the conventional coil manufacturing methods are that a bobbin wound with a wire unavoidably has a great thickness in order to withstand a mechanical force applied by the wound wire, and consequently becomes heavy; some turns of a coil are superposed on each other, thus increasing the thickness of the coil and a bobbin; and some portions of the coil become electromagnetically inactive, failing to elevate the efficiency of a motor comprising such defective coil. These undesirable events take place not only in a cylindrical motor coil, but also in any other type of motor coil.
It is accordingly, an object of this invention to provide coil elements which can be assembled into a motor coil and which are capable of elevating the performance of an electric motor.
Another object of the invention is to provide a method of manufacturing a motor coil efficiently and at low cost by assembling coil elements.